Hydraulic cylinder by-pass relief valve mechanism



Oct. .23, 1962 R. E. SEXAUER 3,059,622

HYDRAULIC CYLINDER BY-PASS RELIEF VALVE MECHANISM Filed Dec. 30, 1960 32 I I 3d Nl/ENTOE .41? GEN Eg United States Patent Ofltice 3,659,622 Patented Oct. 23, 1962 3,059,622 HYDRAULIC CYLTNTDER EY-PASd RELilEF VALVE MECHANISM Russell E. Sexauer, Oak Park, Ili., assignor to International Harvester Company, Chicago, IlL, a corporation of Illinois Filed Dec. 31), 196i), Ser. No. 79,595 7 Claims. ((31. 1211-68) This invention relates to fluid extensible devices and more particularly to a hydraulic ram-type mechanism. More specifically the invention relates to a fluid bypass mechanism on a hydraulic cylinder and piston device.

Certain fluid extensible devices are of the two-way type wherein fluid under pressure may be directed to opposite ends of the fluid cylinder for providing reciprocation under power of the piston and piston rod assembly. In these devices it is frequently desirable to provide a by-pass valve in the piston which, when the piston has arrived at the end of its stroke may by-pass fluid from the chamber under pressure to a chamber on the opposite side of the piston for discharge of the said fluid back to the source of pressure. Such devices generally also are constructed to operate in the same manner when the movement of the piston is reversed and it arrives at the opposite end of the cylinder whereupon by-pass of the fluid under pressure is again achieved. It is a prime object of this invention to provide an improved, simple and structurally sound and effective by-pass mechanism for a hydraulic type extensible device.

Another object of the invention is to provide an improved by-pass mechanism for a fluid extensible device having a by-pass valve movable in response to an actuating element when the cylinder has reached the end of its stroke, said by-pass valve being entirely disposed and movable within the piston of the device.

A still further object is to provide an improved bypass valve =and actuating mechanism disposed within the piston of a fluid extensible device particularly effective for small diameter cylinders, the said device being simple in manufacture and effective in operation.

A more specific object is to provide an improved bypass arrangement for the piston of a fluid extensible device the said arrangement including an annular chamber provided within the piston and including a movable valve element which is adapted to open passages within the piston when it has reached the end of its stroke, the said mechanism being quickly assembled and disassembled and effecting a positive by-pass of fluid under pressure when the piston has reached its desired position within the cylinder of the device.

These and other objects will become more readily apparent from a reading of the description when examined in connection with the accompanying sheet of drawings:

In the drawing:

FIGURE 1 is a cross-sectional view through a fluid extensible device showing portions of a cylinder and showing a piston and by-pass arrangement;

FIGURE 2 is a cross-sectional view taken substantially along the line 2-2 of FIGURE 1;

FIGURE 3 is a cross-sectional view taken substantially along the line 3-3 of FIGURE 1;

FIGURE 4 is a fragmentary cross-sectional view of a piston and fluid by-pass mechanism showing an actuating element adapted to move, a valve element as the piston arrives at the end of its stroke; and

FIGURE 5 is a reduced cross-sectional view of a fluid extensible device showing certain portions of a piston in elevation.

Referring now particularly to FIGURE 1, a fluid extensi-ble device is generally referred to by the reference character 10. The fluid extensible device 10 comprises a fluid cylinder 11 having at one end an end closure member or cap 12 which may be suitably connected to the cylinder by connections not shown. The closure member 12 comprises an axially disposed recess 13. The other end of the cylinder 11 is also closed by means of a cap 14 having a bore 14' as best shown in FIGURE 5.

A piston 15 is reciprocally positioned within the fluid cylinder 11. The piston 15 with the fluid cylinder 11 provides on opposite sides of said piston 15 a chamber 16 and a chamber 17. A fluid connection 18 is in com munication with the chamber 16 and a fluid connection 19 communicates with the chamber 17. The fluid connections 18 and 19 may be placed in communication with a suitable source of fluid pressure (not shown). The piston 15 comprises a pair of axially disposed piston members 20 and 21. A piston ring 22 is connected to the piston member 20 in conventional manner for engaging the inner surface of the fluid cylinder 11.

The piston member 20 is also provided with an inner flat face 23 and the piston member 21 is provided with a flat face and an annular undercut portion 24 which supports a spacer ring 25. The spacer ring 25 is also in engagement with the flat face 23 of the piston member 20 as shown in FIGURE 1. The piston members 20 and 21 respectively include annular grooves 26 and 27 which may contain suitable packing elements 23 and 29 in tight sliding engagement with respect to the inner wall of the cylinder 11. A piston rod is indicated at 30, the said rod 30 including an extension 31 which projects through bores 33 and 32 respectively in the members 21 and 20. The reduced extension 31 is provided with suitable threads and a nut 34 tightly locks the members 20 and 21 in spaced engagement provided by the spacer ring 25. The surface 23 is a finely machined surface against which the spacer ring 25 abuts. In assembly the members 20 and 21 are merely placed into mating engagement with the extension 31 and upon tightening of the nut 34 the assembly is completed. It is unnecessary to spend time in the aligning of the piston members and the spacer ring between the piston members establishes the valve ring clearances necessary and provides the structural elements that permit adequate torquing or tightening of the extension 31 and nut 34. i

The spacer ring 25 with the members 20' and 21 pro vide an annular by-pass chamber designated at 35. A valve ring 36 having an opening 36 encircling the threaded extension 31 is axially slidable or movable within the by-pass chamber 35, the outer edges of said ring sliding on the inner surfaces 25' of the spacer ring 25.

A plurality of radially disposed passages 37, as shown in FIGURES l and 3, are provided on the piston member 20. The passages 37 provide for communication between the chamber 16 and the by-pass chamber 35. A plurality of bores 38 likewise are provided in the piston member 20, the said bores 38 also communicating with enlarged bores 39 provided inwardly of the face 23. Pins 40 are slidingly disposed within the bores 38, the said pins including heads 41 which may be recessed within the bores 39 during a certain position of said pins. The pins 40 are actuating elements which may project into the chamber 16 in a certain position or which may project into the chamber 35 as shown in FIGURE l. The piston member 21 also is provided with a plurality of radially spaced axially extending passages 42 which communicate with the chamber 17 and with the by-pass chamber 35. The member 21 also includes a plurality of actually extending bores 43 which slidably support pins 44 having enlarged heads 45 which are adapted to be recessed within enlarged bores 46.

In the operation fluid pressure from a suitable source (not shown) may be directed either to the fluid connection 18 or the fluid connection 19. In FIGURE 1, for instance, fluid under pressure is directed to the chamber 16 which forces the piston to the right. The fluid under pressure enters through the passages 37 into the bypass chamber and forces the valve 36 in closed position with respect to the passages 42 until the piston is moved to its immediate or extreme right-hand position Whereupon the pins 44 will engage a shoulder or stop 47 on the cap 14 whereupon the said pins 44 will be moved to the left and project into the bypass chamber 35 thereupon moving the valve element 36 also to the left to uncover the passages 42 whereupon the passages 37 and 42 are now in communication and fluid from the chamber 16 by-passes to the chamber 17 whereupon it leaves the chamber through the connection 19 again to a fluid reservoir or suitable source of pressure. In FIGURE 4, the piston 15 is shown as it is moved to the left end of the cylinder 11. In this view, the piston 15 is shown approaching the stop 47 and the pins are engaging the stop 47 whereupon continued movement of the piston 15 to the left, the pins 40 move to the right into the by-pass chamber 35 and unseat the valve element 36 from the passages 37 so that the passages 37 and 4-2 are now in communication and fluid under pressure from the chamber 17 will bypass to the chamber 16. Thus it is apparent that an eflective and positive by-pass arrangement has been disclosed. The by-pass arrangement and piston structure is simple in operation with relatively few moving parts and can be easily assembled and disassembled. Furthermore, the bypass arrangement is completely enclosed within the piston itself and operation is positive in view of the novel arrangement of the pins 40 and 44.

Thus it is believed that the objects of the invention have been fully achieved and that modifications may be made without departing from the spirit of the invention as disclosed or from the scope thereof as defined in the appended claims.

What is claimed is:

1. In a fluid extensible device comprising a cylinder, a piston reciprocably positioned within said cylinder and providing at axially spaced opposite sides thereof first and second chambers within said cylinder, and first and second fluid pressure connections on said cylinder communicating respectively with said first and second chambers; a fluid by-pass valve mechanism in said piston comprising, first and second axially spaced annular piston members, one of said piston members including a peripherally extending piston ring engaging said cylinder in sliding relation, a spacer ring disposed between adjacent portions of said piston members to provide an annular by-pass chamber, means connecting together said spacer ring and piston members, said first piston member having a plurality of first axially extending and radially spaced passages communicating with said first chamber and said by-pass chamber, said second piston member having a plurality of second axially extending and radially spaced passages communicating with said by-pass chamber and said second chamber, said first and second piston members including first and second axially extending and radially spaced bores, first and second actuating pins respectively slidingly disposed in said bores, said pins being adapted to project into said first and second chambers and into said bypass chamber, and a valve ring axially movable within said by-pass chamber, said fluid cylinder including first and second stop elements respectively in said first and second chambers, said piston being movable during pressure in one of said chambers toward one end of said fluid cylinders whereby said valve ring closes the passages in one of said piston members, whereupon the pins of one of said piston members engage one of said stops and said last-mentioned pins are moved into said by-pass chamber and move said valve ring axially from said last-mentioned passages whereby fluid under pressure bypasses from one chamber to the other.

2. In a fluid extensible device comprising a cylinder, a piston reciprocably positioned within said cylinder and providing at axially spaced opposite sides thereof first and second chambers within said cylinder, and first and second fluid pressure connections on said cylinder communicating respectively with said first and second chambers; a fluid by-pass valve mechanism in said piston comprising, first and second axially spaced annular piston members engaging said cylinder in sliding relation, a spacer ring disposed between adjacent portions of said piston members to provide an annular by-pass chamber, means connecting together said spacer ring and piston members, said first piston member having a plurality of first axially extending and radially spaced passages communicating with said first chamber and said by-pass chamber, said second piston member having a plurality of second axially extending and radially spaced passages communicating with said by-pass chamber and said second chamber, said first and second piston members ineluding first and second axially extending and radially spaced bores, first and second actuating pins respectively slidingly disposed in said bores, said pins being adapted to project into said first and second chambers and into said by-pass chamber, and a valve ring axially movable within said by-pass chamber, said fluid cylinder including first and second stop elements respectively in said first and second chambers, said piston being movable during pressure in one of said chambers toward one end of said fluid cylinder whereby said valve ring closes the passages in one of said piston members, whereupon the pins of one of said piston members engage one of said stops and said last-mentioned pins are moved into said by-pass chamber and move said valve ring axially from said last-mentioned passages whereby fluid under pressure bypasses from one chamber to the other.

3. In a fluid extensible device comprising a cylinder, a piston reciprocably positioned within said cylinder and providing at axially spaced opposite sides thereof first and second chambers within said cylinder, and first and second fluid pressure connections on said cylinder communicating respectively with said first and second chambers; a fluid by-pass valve mechanism in said piston comprising, first and second axially spaced annular piston members engaging said cylinder in sliding relation, a spacer disposed between adjacent portions of said piston members to provide a by-pass chamber, means connecting together said spacer ring and piston members, said first piston members having a plurality of first axially extending and radially spaced passages communicating with said first chamber and said by-pass chamber, said second piston member having a plurality of second axially extending and radially spaced passages communicating with said by-pass chamber and said second chamber, said first and second piston members including first and second axially extending and radially spaced bores, first and second actuating pins respectively slidingly disposed in said bores, said pins being adapted to project into said first and second chambers and into said by-pass chamer, and a valve ring axially movable within said by-pass chamber, said fluid cylinder including first and second stop elements respectively in said first and second chambers, said piston being movable during pressure in one of said chambers toward one end of said fluid cylinders whereby said valve ring closes the passages in one of said piston members, whereupon the pin of one of said piston members engage one of said stops and said lastmentioned pins are moved into said by-pass chamber and said valve ring is moved axially from said last-mentioned passages whereby fluid under pressure bypasses from one chamber to the other.

4. In a fluid extensible device comprising a cylinder, a piston reciprocably positioned Within said cylinder and providing at axially spaced opposite sides thereof first and second chambers within said cylinder, and first and second fluid pressure connections on said cylinder communicating respectively with said first and second chambers; a fluid bypass valve mechanism in said piston comprising, first and second axially spaced annular piston members engaging said cylinder in sliding relation, a spacer disposed between adjacent portions of said piston members to provide a by-pass chamber, means connecting together said spacer ring and piston members, said first piston member having a plurality of first axially extending passages communicating with said first chamber and said by-pass chamber, said second piston member having a plurality of second axially extending passages communicating with said by-pass chamber and said second chamber, said first and second piston members including first and second axially extending bores, first and second actuating pins respectively slidingly disposed in said bores, said pins being adapted to project into said first and second chambers and into said by-pass chamber, and a valve ring axially movable within said by-pass chamber, said fluid cylinder including first and second stop elements respectively in said first and second chambers, said piston being movable during pressure in one of said chambers toward one end of said fluid cylinders whereby said valve ring closes the passages in one of said piston members, whereupon the pins of one of said piston members engage one of said stops and said last-mentioned pins are moved into said by-pass chamber and move said valve ring axially from said last-mentioned passages whereby fluid under pressure bypasses from one chamber to the other.

5. In a fluid extensible device comprising a cylinder, a piston and piston rod assembly positioned for reciprocation within said cylinder and providing therewith on axially spaced opposed sides of said piston, fluid chambers, and means directing fluid under pressure to said chambers whereby said piston may be moved from one end of said cylinder to the other; a fluid by-pass mechanism Within said piston comprising axially spaced piston members providing therebetween a by-pass chamber, an axially extending passage on each piston member adapted to communicate with said by-pass chamber and with the chambers on said opposed sides of said piston, a valve in said by-pass chamber axially movable to alternately close said passages, said piston members each including an axially extending bore, actuating pins slidingly disposed in said bores, said piston during pressure in one chamber being movable whereby fluid under pressure from said one chamber is directed through one of said passages to said by-pass chamber and moves said valve in sealing relation with respect to said other passage, and means at opposite ends of said cylinder engaged by one of said pins during movement of said piston to the end of its stroke whereby said pin moves said valve axially from sealing relation with said last-mentioned passage whereby fluid will bypass from said one chamber to the other.

6. In a fluid extensible device comprising a cylinder, a piston and piston rod assembly positioned for reciprocation Within said cylinder and providing therewith on axially spaced opposed sides of said piston, fluid chambers, and means directing fluid under pressure to said chambers whereby said piston may be moved from one end of said cylinder to the other; a fluid by-pass mechanism within said piston comprising axially spaced piston members providing therebetween a by-pass chamber, an axially extending passage on each piston member adapted to communicate with said by-pass chamber and with the chambers on said opposed sides of said piston, a valve in said by-pass chamber movable to alternately close said passages, said piston members each including an axially extending bore, actuating elements slidingly disposed in said bores, said piston during pressure in one chamber being movable whereby fluid under pressure from said one chamber is directed through one of said passages to said by-pass chamber and moves said valve in sealing relation with respect to said other passage, and means at opposite ends of said cylinder engaged by one of said actuating elements during movement of said piston to the end of its stroke whereby said last-mentioned actuating element moves said valve from sealing relation with said last-mentioned passage whereby fluid will bypass from said one chamber to the other.

7. In a fluid extensible device comprising a cylinder, a piston and rod assembly positioned for reciprocation within said cylinder and providing therewith on axially spaced opposed sides of said piston, first and second fluid chambers, means directing fluid under pressure to said second chamber, and means to discharge fluid from said first chamber; a fluid by-pass mechanism within said piston comprising first and second separable axially spaced piston members, a spacer ring positioned between adjacent portions of said piston members, means connecting said piston members and spacer ring together to provide therebetween and with said spacer ring a by-pass chamber, first and second axially extending passages respectively on said first and second piston members adapted to respectively communicate with said first and second chambers and the by-pass chamber, a valve in said by-pass chamber movable to close and open said first passage, said first piston member including an axially extending bore, an actuating element slidingly disposed in said bore, said piston during pressure in said second chamber being movable and fluid is directed through said second passage to said by-pass chamber and said valve is moved in sealing relation to close said first passage, and means in said first chamber engaged by said actuating element during movement of said piston to the end of its stroke whereby said actuating element moves said valve from sealing relation relative to said first passage whereby fluid will by-pass to said first chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,637,259 Acton May 5, 1953 2,676,663 Smith r Apr. 27, 1954 2,709,420 Fullwood et al May 31, 1955 FOREIGN PATENTS 1,125,999 France July 23, 1956 

